Hydrostatic siphon circulation control for thermosiphon heat transfer systems



June 20, 1950 M. E. FIENE 2,512,318

HYDROSTATIC SIPHON CIRCULATION CONTROL FOR THERMOSIPHON HEAT TRANSFER SYSTEMS Filed May 14, 1947 Inventor: Marcus E.Fiene,Deceasd, Clara E. Fiene,Administratmx,

by @Lvgfitw Attorney.

Patented June 20, 1950 HYDROSTKTIQ sIrHoN CIRCULATION CON- 'rnon FGWTHERAMO'SIPHON HEAT TRANS FE-BbSY-ST-EMS MarcusE. Fiene, deceased, we Sootia INaE, by Clara EL Fiene, administnatnix, lirie llta; av

sigr'fo'r to Y ration of New York General Electric Company, arcorpo Application May'14, 1947; seriarNot mgrso ihe invention relates to thermosip'hon heat transfer systems, particularly systems including aboiler or other heated liquidcontainer from vantageous in a; hot water boiler heating. system 7 for homes, particularly. where the boiler heats domestic hot water in both summer and winter and the improved hydrostatic siphon circulation control of the present invention is operated under the control-f aroom thermostat so as to control the circulation of the hot water to the heat exchanger for heatingthe rooms in the winter while preventing transfer of heat to the rooms in summer. 4

Thus, another object is to provide improved thermostatic controlarrangements for stopping and starting thermosiphon circulation by rendering a hydrostatic siphon in the thermosiphon systemefiective orinefiective.

Another object is toprovide animproved in" verted U-tube siphon-type of thermosi'phon circulation control arranged to gas-lock and thereby break the thermosiphon liquid circulating circuit} together with improved hydrostatic liquid level control means for raising and lowering. the liquid level in the inverted U-tube siphon so as to selectively start and stop the thermosiphon liquid circulation through the tube and thereby control the heattransfer actiona Furtherobjec'ts and advantages of the inven-- tion will appear in the renewing description 'of the aecoiripanying' drawing inwhich Fig. -1 is a schematic side view, partly in section, of a hot water boiler furnace thermo'siphon heat exraiigersystem embodying'the improvements of the invention in a preferred form; Fig. Zis a partial sectional view or the heat exchanger shown in Fig. l"; and Fig. '3"i's a schematic view of a modified "form oftherxno'siphon heat exchange system embodying the invention.

As shown in Fig. 1, the thermosiphon heat exchange medium circulating system indicated generally byth'e' reference character 1U includes the hotwa'ter boiler "ll andthe heat exchanger [2 which rejinterconi ected at the bottom by the conduit 13 and "at the top by the improved hydrostatic siphon circulation control of the present invention indicated generally by the reference character 13. "The eoilerfurnace ll is 12 Claims. (arma shown. as oft. the: conventionah: hand-coal-fired;

typeprovided witlnthedraft damper I15; and. ciieclndanrpem Iii for regulating; the; fire. These; dampers' a're shown interconnected in the usual. to -beoperated by-the-tiltinglever l1 thatis actuated: by: the boiler pressure-responsive bellows The-tilting lever; llalso carriesaetiltina mercury switch K9; Boileri it is provided with) a domestichotwater: heater all at a the usual form.

dine heat exchanger n consistent afinned tube coir 23 enclosedwithirr the air duct 24 through whichtlierair is circulated by=a blower 25 driven by the motor 26 to transfer heatnfironrthe coil ie intotne rooms at theihouse. An automatic air vent-valvefiis provided: for venting air from the coil 13i v The improved hydrostatic. siphon circulation control m ter: thethermosipho-n system consists in the 'preferredvtorm'showninEig. l of the closed. and heat insulated casing; 28 throushethe bottom of i which the two: conduits 2a and 30 extendv so as to-io'rnran inverted U-type siphon in the. upper leg of" the thermosiphon circulating. syssv temp. Thedotted line. indicates the normal; water levelinathe: hot water boiler II and the dotted lines alviand 33: indicate the corresponding waterlea/e1,v in the conduits 29a and 30. Hence, the inverted u-siphon l4 extending abovethe water level normally introduces abreak in the thermosiphonwater circulating circuit and thus normally preventscirculation of the hot water froirrt'he boiler H to the heat exchanger 1 2.

- The steam or vapor space- 34 in. the topof. thehot water boiler l l: is interconnected with the interior of-the-siphoncasing 28'by means ofthe pressure equalizing :pipero i that is provided with the normally' open electromagnetically closed valve to forcontrolling communication between the boiler vapor space-34- and the interior o'i the casing zar- The finned vapor condenser tube -38 is interconnected w'ith the *interior of the casing 28 and. is located-inside a-loop ita extending from the air dirct 2 5- opposite the finned heat exchange coil 23; Preferably 'the loop 24a. is provided with a layer of heat'lnsulating material 39- andalso with an -air flow barrier dB-seas to insure "that hea'tds released from'the-finned tube 38 only when air is being circulated by the blower 25. Thus, the'finrie'd-tube -38 serves as a vapor condenserio'r condensing vapors-accumulated within the casing: zowith the condensing action depe'ndentuponoperation ofblower 25'. 1 u 1 "The blower driving motorifi and the operating electromagnet 35a of valve 36 are interconnected primary connected across the supply lines L1, L2.

Operation of Figsfl and 2 With the hot water boiler I I in normal operation, the pressure bellows 18 will regulate the position of dampers i5 and 16 so as normally to maintain the boiler water at a predetermined temperature sufficient to supply the needs of the domestic hot water heater 2! both summerand winter as I long as an adequate supply of coal or othe'rfuel is provided. In the summer, both the electromagnetio valve 35 and the motor 26 are maintained deenergized by relay 42 as shown in Fig. 1.since no heat is required in therooms. (Under these conditions the valve 35 is open and the pressure equalizing pipe 35 is effective to equalize the pressure between the vapor space 34 and the interior of casing 28 so that the water level indicated by the dotted lines 3|, 32 audit; is maintained. As a result, the thermosiphon. circulating circuit is broken and no heat is transferred from the boiler H to the exchanger 12. Moreover, due to the heat insulation around the loop 24a, little, if any, heat is released from the condenser formed by the finned tube 38.

Whenever heat isrequired in the rooms, the

has raised the room temperature suificiently to cause room thermostat 43 to open its contacts, then the relay operating winding 42a is deenergized and the relay contact 42b returns to its normallyopen position in which it is shown so as to deener'gize both the electromagnetic valve 36 and the blower driving motor 26. Upon the opening of valve 35, the pressure within the easing 28 becomes equalized with that in the boiler vapor space 34-. As a result, the water levels 32v and 33, again become aligned with the normal boiler water level 3i. This enables the hydrostatic siphon to break the thermosiphon water circulating circuit and thus prevents further transier'of heat from the boiler H.

In the modified form of the invention shown in Fig. 3,-any heat producing device, such, for

room thermostat 43wi1l close its contacts to energize the relay operating winding 42a and thereby close relay contact 425. Then, in case the contacts of the tilting mercury switch 19 are closed in response to steam pressure, as shown in Fig. 1, the electromagnetic valve 36 will be energized so as to close and thereby interrupt the communication between the, boiler vapor space 34 and the interior of casing 28. The energizing circuit for the electromagnetic valve 36 extends from the supply line L2 through conductor 45, relay contact 42b, conductor 46,.tilting mercury switch l9, conductor. 41', the operating electromagnet 36a for closing va1ve.36, and conductors 48 and 49 to the other supply line L1.

At the same time the blower driving motor 26 until the level 31 is reachedinside the casing 28 where condenser 38 becomes partially flooded. Under these conditions the hydrostatic siphon circulation control I4 of the thermosiphon heat transfer system 10 is rendered effective so as to circulate hot waterfrom boiler H through conduit 29, casing 28, conduit 30, finned coil 23 and return conduit l3. Hence, blowe r 25 will operate to circulate air through the f nned coil 23 to be heated and thus transfer heat into the rooms. At the same time, air being circulated through the loop 24a to cool the condenser 38 and thereby insure that the water le /e131 is maintained within the siphon casing 28.

When the heated air circulating to the room example, as the thyratron tube 50 shown, is maintained at a desired normal operating temperature by means of a thermosiphon heat dissipating systemcontrolled in accordance with the present invention. As shown, thethyratrontube 5!] is surrounded'by a tank or liquid container 51 having the finned heat dissipating coils -52 interconnected therewith through the inverted U-shaped hydrostatic circulation control siphon-53. The casing or tank 5| is filled to the level indicated by the dotted line '54 with a suitable heat transfer liquid whose vapor pressure, at the desired operating temperature of the thyratron-tube50,-is above atmospheric pressure. For example, ethyl ether is a suitable liquid-where an optimum operating temperature of approximately 50 C. or 122 F. is

The inverted U-tube siphon 53 is provided with a tubular condenser 55 provided with fins for dissipating heat therefrom, and connected at the write the interior of anexpansible bellows 56 placed inside the protective casing 51 with a suitable weight 58 compressing the bellows. The bellows 5B, tubular condenser'55' and the upper part of the inverted U-tube '53 are filled-with a suitable non-condensible gas, such as nitrogen, at a pressure somewhat below that of the desired operating vapor pressure of the liquid -filling the casing or tank 5! and-the heat exchange coil 52.

A restricted pressure equalizing tube '60 is interconnectedbetween the'top of the tubular extension El from tank 5| andthe tubular condenser 55 and is'preferably provided with heat dissipating fins as indicated. v

. Operation of Fig. 3

The thermosiphon liquid circulating circuit is maintained broken by the empty siphon 53 during the warming-up T period o i 'the'thyratron tube 50. Howevenwhen the ebullition temperature of the liquid surroundinglthe 'tube 55 is reached, then the vapor pressure :in 'the tubular extension 5! will begin to exceed that of the non-condensible gas above the liquidiinlthe' top of the U-tube 53 and the tubular condenser '55. Thepressure differential thus developed will depress the liquid level 54 inthe tank 51' and"will'corre'spondingly raise'the liquid level 59 in the inverted U-tube 53. I

Therestricted equalizingf'connectmn 60 will tend somewhat to prevent' the variation in liquid level just described, [but with tube '69 suitably restricted the rate'of 'vapor'generation within the tank 5!, due toheating from the thyratron tube 50, will exceed the capacity of the equalizing a result, the liquid level in the inverted U-tube 53 will'rise and the mixture of'vaporandthe vapor is largelywondens'ed --aueto thefheat 3 dissipating'action of'the' fins withwhich the tub'ula'r' condenser "Eff-is provided? The noncon dehsible gas will be-forced into ure-beuows-ss:

sufliciently to establish continuity of the therino siphon circuit;the liquid will flow from the tank dissipating coil 52, and thereby provide-a"cooling effect on the circulated liquid sufficient to maintain the thyratron tube 50 at the desired operating-temperature.-

In case the cooling effect should become great enough to drop the temperature ofthezliquid in tank 5| below the desired operating temperature, then ,the' vapor pressure in the tubular extension 6l":wi'll'ftend"to" fall below thatofthe gas"inbllows 156*. Theweight58'Will'therefore compress bellows 5Gand causethe inert gas to be'forc'ed through the tubular condenser 55 into the inverted U-tube 53. As a result, the continuity of the thermosiphon circulating circuit will be interrupted with a corresponding reduction in the cooling action of the finned coils 52.

It will be apparent to those skilled in the art that this modified form of the invention is not limited to cooling a thyratron tube but may be applied with equal advantage to cooling other heat producing devices such, for example, as internal combustion engines or the like. In this latter case where a lower normal operating temperature is desired, methyl alcohol or other suitable liquid may be used as the circulating heat transfer medium.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In combination, a heat producing device, a liquid circulating system of the thermosiphonlc type for dissipating heat therefrom, a liquid trap connected in said circulating system, means for introducing condensible vapor into said trap, and means including a condenser for condensing said vapor to vary the pressure in said trap and thereby control the thermosiphonic circulation in said system.

2. In combination, a heat producing device, a liquid circulating system of the thermosiphonic type for dissipating heat therefrom, said heat producing device including a container arranged to hold a body of liquid at a predetermined level therein with a vapor space above the liquid, a liquid trap connected in said circulating system, said trap having a vapor space connected with the vapor space of said heat producing device, means for introducing condensible vapor into said vapor spaces, and means including a condenser arranged to condense vapor insaid trap for maintaining a predetermined pressure differential between said vapor spaces to control the thermosiphonic circulation in said system.

3. In combination, a heat producing device, a liquid circulating system of the thermosiphonio type for dissipating heat therefrom, a liquid trap connected in said circulating system for controlling the circulation therein, means for introducing condensible vapor into said trap to stop thermosiphon circulation therethrough and means for condensing said vapor to start the thermosiphon circulation.

4. In combination, a heated liquid container, a liquid circulating system of the thermosiphonic type for dissipating heat therefrom, said container being arranged to hold a body of liquid at a predetrfnined leve'l therei "witl'fa weeds-space abov fl'iefliqilid '"liquid trap conneoted insaid above""saidlevel,- means -i eluding ava-por' pressure equalizing connection between said 'fco'ntainei and; said trap for inti'oducing con'densible' vapor into said-trap, and}? int'ain'ing a predetermined pres e tweenthe -'vapor-in said con a" r* 6. In dmbiaaeoawana heat'prdducing 'dev e" having athimosiphbh heat transfer nidiiim circulating system of a liquid trap connected in said circulating system and provided with thermodynamic control means including a, vapor pressure equalizing connection having anelectromagnetic control valve and a vapor condenser for varying the level of the medium in said trap to start and stop the thermosiphon circulation, and means including a thermostatic switch for controlling the energization of said valve.

'7. In combination, a thermosiphon heat transfer liquid circulating system including a heated liquid container having a liquid level therein and a vapor space above said level, means including a liquid trap extended above said level and having a vapor pressure equalizing connection with said vapor space, vapor condenser means for condensing vapor in said trap, and thermostaticaily controlled means for reversely unbalancing the effectiveness of said connection and said condenser to start and stop the thermosiphon circulation in said system.

8. In combination, a thermosiphon heat transfer liquid circulating system including a heated liquid container having a liquid level therein and a vapor space above said level, means including a trap extended above said level and having a vapor pressure equalizing connection with said vapor space for stopping thermosiphon circulation from said container, vapor condenser means for condensing vapor in said trap, and thermostatic means for rendering said condenser means effective and relatively ineffective.

9. In combination, a thermosiphon heat trans-- fer liquid circulating system including a heated liquid container having a liquid level therein and a vapor space above said level, means including a liquid trap extended above said level and hav-- ing a vapor pressure equalizing connection with. said vapor space for stopping thermosiphon circulation from said container, vapor condenser means for condensing vapor in said trap, and, vapor pressure responsive means for rendering said condenser means effective and relatively ineffective.

10. In combination, a thermosiphon heat transfer system including a hot water boiler hav. ing a vapor space above the water level therein, firing control means for maintaining the water in said boiler at a predetermined temperature, means including a trap extending above the water level of said boiler and having a vapor pressure equalizing connection with said vapor space for stopping thermosiphon circulation from said boiler, condenser means interconnected with said trap for normally tending to condense vapor in said trap, and means including a thermostatic control valve for closing said equalizing connectionto start said thermosiphon circulation.

4 11. In combination with a heat producing device having thermosiphon heat transfer medium circulating system for dissipating heat therefrom, of a liquid trap connected in said circulating system for controlling the circulation therein, means for introducing noncondensible gas into said trap to stop thermosiphon circulation therethrough, and pressure responsive means for withdrawing said noncondensible gas from said trap to start the thermosiphon circulation.

12, In combination with a heat producing device having a thermosiphon heat transfer medium circulating system for dissipating heat therefrom, of a liquid trap connected in said circulating system for controlling the circulation therein, means including a gas filled bellows connected with said trap and provided with biasing means for mainthe thermosiphon circulation when the temperature of said medium exceeds a predetermined value.

CLARA E. FIENE,

Administratrix of the Estate of Marcus E. Fiene,

Deceased.

REFERENCES CITED The following references are of record in the filevof this patent:

UNITED STATES PATENTS I Date Number Name r 809,164 Beanes et al. Jan. 2, 1906 29 1,952,475 Tidd Mar. 27, 1934 2,343,856 Tidd Mar. 7, 1944 

